U.S. patent application number 16/395852 was filed with the patent office on 2019-08-15 for method of fabricating a photomask.
This patent application is currently assigned to SK hynix Inc.. The applicant listed for this patent is SK hynix Inc.. Invention is credited to Dong Sik JANG.
Application Number | 20190250500 16/395852 |
Document ID | / |
Family ID | 58664017 |
Filed Date | 2019-08-15 |
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United States Patent
Application |
20190250500 |
Kind Code |
A1 |
JANG; Dong Sik |
August 15, 2019 |
METHOD OF FABRICATING A PHOTOMASK
Abstract
A method of fabricating a photomask comprising providing a
photomask blank including a phase shifting layer, a first light
blocking layer, a first resist layer, a second light blocking layer
and a second resist layer stacked sequentially in this order on a
substrate, forming second resist patterns, forming second light
blocking patterns, forming first resist patterns, forming first
light blocking patterns and phase shifting patterns, removing the
first resist patterns, and selectively removing at least one of the
first light blocking patterns, wherein the second resist layer has
a thickness such that all of the second resist layer is removed
while the first resist layer is patterned for exposing the second
light blocking layer.
Inventors: |
JANG; Dong Sik;
(Chungcheongbuk-do, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SK hynix Inc. |
Gyeonggi-do |
|
KR |
|
|
Assignee: |
SK hynix Inc.
|
Family ID: |
58664017 |
Appl. No.: |
16/395852 |
Filed: |
April 26, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
15064348 |
Mar 8, 2016 |
10317791 |
|
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16395852 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G03F 1/80 20130101; G03F
1/26 20130101; G03F 1/78 20130101 |
International
Class: |
G03F 1/26 20060101
G03F001/26; G03F 1/78 20060101 G03F001/78; G03F 1/80 20060101
G03F001/80 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 5, 2015 |
KR |
10-2015-0154958 |
Claims
1. A method of fabricating a photomask, the method comprising:
providing a photomask blank including a phase shifting layer, a
first light blocking layer, a first resist layer, a second light
blocking layer and a second resist layer stacked sequentially in
this order on a substrate; forming second resist patterns by
patterning the second resist layer; forming second light blocking
patterns by patterning the second light blocking layer using an
etch process employing the second resist patterns as etch masks;
forming first resist patterns by patterning the first resist layer
using an etch process employing the second light blocking patterns
as etch masks; forming first light blocking patterns and phase
shifting patterns by patterning the first light blocking layer and
the phase shifting layer using an etch process employing the first
resist patterns as etch masks; removing the first resist patterns;
and selectively removing at least one of the first light blocking
patterns, wherein the second resist layer has a thickness such that
all of the second resist layer is removed while the first resist
layer is patterned for exposing the second light blocking
layer.
2. The method of claim 1, wherein the forming of the second light
blocking patterns is performed by patterning the second light
blocking layer using an anisotropic dry etch process employing an
oxygen gas as an etch gas.
3. The method of claim 1, wherein the forming of the first resist
pattern includes removing the second resist patterns during the
patterning of the first resist layer.
4. The method of claim 1, wherein the selective removing of at
least one of the first light blocking patterns includes: forming a
third resist pattern that exposes a pattern region of the substrate
and covers a frame region of the substrate; removing the first
light blocking patterns on the pattern region of the substrate; and
removing the third resist pattern.
5. The method of claim 1, wherein the first light blocking layer
and the second light blocking layer have a light transmittance of
at most 5%, the first light blocking layer includes a chrome (Cr)
layer, an aluminum (Al) layer, a tantalum (Ta) layer or a titanium
nitride (TiN) layer, and wherein the second light blocking layer is
composed of material added oxygen atoms to the same material
employed for the first light blocking layer.
6. A method of fabricating a photomask, the method comprising:
providing a photomask blank including a first light blocking layer,
a first resist layer, a second light blocking layer and a second
resist layer which are stacked sequentially on a substrate; forming
second resist patterns by patterning the second resist layer;
forming second light blocking patterns by patterning the second
light blocking layer using an etch process employing the second
resist patterns as etch masks; forming first resist patterns by
patterning the first resist layer using an etch process employing
the second light blocking patterns as etch masks; forming first
light blocking patterns by patterning the first light blocking
layer using an etch process employing the first resist patterns as
etch masks; and removing the first resist patterns, wherein the
second resist layer has a thickness such that all of the second
resist layer is removed while the first resist layer is patterned
for exposing the second light blocking layer.
7. The method of claim 6, wherein the forming of the second light
blocking patterns is performed by patterning the second light
blocking layer using an anisotropic dry etch process that employs
an oxygen gas as an etch gas.
8. The method of claim 6, wherein the forming of the first resist
pattern includes removing the second resist patterns during the
pattering of the first resist layer.
9. The method of claim 6, wherein the first light blocking layer
and the second light blocking layer have a light transmittance of
at most 5%, the first light blocking layer includes a chrome (Cr)
layer, an aluminum (Al) layer, a tantalum (Ta) layer or a titanium
nitride (TiN) layer, and wherein the second light blocking layer is
composed of material added oxygen atoms to the same material
employed for the first light blocking layer.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application is a continuation application of
U.S. patent application Ser. No. 15/064,348 filed on Mar. 8, 2016,
which claims priority under 35 U.S.C 119(a) to Korean Patent
Application No. 10-2015-0154958, filed on Nov. 5, 2015, which is
incorporated herein by reference in its entirety.
BACKGROUND
1. Technical Field
[0002] Various embodiments of the present disclosure relate to a
method of fabricating a photomask.
2. Related Art
[0003] Highly integrated semiconductor devices exhibit improved
operation speed and lower power consumption. Various advanced
process technologies have been proposed for reducing the minimum
feature size of circuit patterns, such as interconnection patterns,
and contact hole patterns employed for electrically connecting the
interconnection patterns. For example, various advanced
photolithography technologies have been used for forming fine
patterns. Generally, photolithography processes employ photomasks,
exposure apparatuses and resist materials all of which are
important in minimizing the size of the circuit patterns.
[0004] Generally, forming accurate photomask patterns on a mask
substrate require to accurately pattern a resist layer of a
photomask blank. Generally, a phase shift photomask blank may
include a phase shifting layer, a light blocking layer and a resist
layer which are stacked sequentially on a substrate. Typically, the
resist layer is patterned for forming resist patterns, whereas the
light blocking and the phase shifting layers are patterned using
the resist patterns for forming light blocking patterns and phase
shifting patterns, respectively. In such a case, the pitch sizes of
the light blocking patterns and the phase shifting patterns are
determined by the pitch size of the resist patterns. The resist
patterns may act as etch buffers or etch masks while an etch
process for patterning the light blocking layer is performed. Thus,
according to existing processes, the resist layer should be formed
to have at least a sufficient thickness for accommodating the above
processes. Increasing the thickness of the resist layer generally
may improve the accuracy of the light blocking and the phase
shifting patterns, however, it may make it more difficult to
accurately pattern the resist layer. Accordingly, it is generally
difficult to form accurate light blocking and phase shifting
patterns.
SUMMARY
[0005] Various embodiments are directed to methods of fabricating
photomasks.
[0006] According to an embodiment, there is provided a method of
fabricating a photomask. The method includes providing a photomask
blank having a phase shifting layer, a first light blocking layer,
a first resist layer, a second light blocking layer and a second
resist layer which are stacked sequentially in this order on a
substrate. The second resist patterns are formed by patterning the
second resist layer. The second light blocking patterns are formed
by patterning the second light blocking layer using an etch process
employing the second resist patterns as etch masks. The first
resist patterns are formed by patterning the first resist layer
using an etch process employing the second light blocking patterns
as etch masks. The first light blocking patterns and the phase
shifting patterns are formed by patterning the first light blocking
layer and the phase shifting patterns by patterning the first light
blocking layer and the phase shifting layer using an etch process
employing the first resist patterns as etch masks. The first resist
patterns are then removed. At least one of the first light blocking
patterns is selectively removed. The second resist layer has a
thickness such that all of the second resist layer is removed while
the first resist layer is patterned for exposing the second light
blocking layer.
[0007] According to other embodiment, there is provided a method of
fabricating a photomask. The method includes providing a photomask
blank having a first light blocking layer, a first resist layer, a
second light blocking layer and a second resist layer which are
stacked sequentially on a substrate. The second resist patterns are
formed by patterning the second resist layer. The second light
blocking patterns are formed by patterning the second light
blocking layer using an etch process employing the second resist
patterns as etch masks. The first resist patterns are formed by
patterning the first resist layer using an etch process employing
the second light blocking patterns as etch masks. The first light
blocking patterns by patterning the first light blocking layer
using an etch process employing the first resist patterns as etch
masks. The first resist patterns are then removed. The second
resist layer has a thickness such that all of the second resist
layer is removed while the first resist layer is patterned for
exposing the second light blocking layer.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] Various embodiments of the present disclosure will become
more apparent in view of the attached drawings and accompanying
detailed description, in which:
[0009] FIG. 1 is a cross-sectional view of a phase shift photomask
blank, according to an embodiment of the present disclosure;
[0010] FIGS. 2 to 7 are cross-sectional views illustrating a method
of fabricating a phase shift photomask using the phase shift
photomask blank shown in FIG. 1;
[0011] FIG. 8 is a cross-sectional view of a binary photomask blank
according to an embodiment of the present disclosure; and
[0012] FIGS. 9 to 13 are cross-sectional views illustrating a
method of fabricating a binary photomask using the binary photomask
blank shown in FIG. 8.
DESCRIPTION OF SPECIFIC EMBODIMENTS
[0013] It will be understood that although the terms first, second,
third and so on may be used herein to describe various elements,
these elements should not be limited by these terms. These terms
are only used to distinguish one element from another element.
Thus, a first element in some embodiments could be termed a second
element in other embodiments without departing from the teachings
of the present disclosure. It will also be understood that when an
element is referred to as being located "on," "over," "above,"
"under," "beneath," "below," "side," or "aside" another element, it
may directly contact the other element, or at least one intervening
element may be present therebetween. Accordingly, the terms such as
"on," "over," "above," "under," "beneath," "below," "side,"
"aside," and the like that are used herein are for the purpose of
describing only a position relationship of two elements and are not
intended to limit the scope of the present disclosure. It will be
further understood that when an element is referred to as being
"connected" or "coupled" to another element, it can be directly
connected or coupled to the other element or intervening elements
may be present. In contrast, when an element is referred to as
being "directly connected" or "directly coupled" to another
element, there are no intervening elements present.
[0014] FIG. 1 is a cross-sectional view of a phase shift photomask
blank 100 according to an embodiment.
[0015] Referring to FIG. 1, the phase shift photomask blank 100 may
include a phase shifting layer 120, a first light blocking layer
130, a first resist layer 140, a second light blocking layer 150
and a second resist layer 160 all of which are stacked sequentially
on a substrate 110. In an embodiment the order of the layers may be
as shown in FIG. 1.
[0016] The substrate 110 may be or include a light transmitting
material, for example, a quartz material, a glass material, a
silicon material, a silicon nitride material or a silicon
oxynitride material.
[0017] The phase shifting layer 120 may be disposed on the
substrate 110. The phase shifting layer 120 may be or include any
suitable material. In an embodiment, the phase shifting layer 120
may be or include a molybdenum silicide (MoSi) layer. The phase
shifting layer 120 may shift a phase of a light passing
therethrough by about 170 degrees to about 190 degrees. That is, a
phase of a light penetrating all of the phase shifting layer 120
and the light transmitting substrate 110 may precede a phase of a
light penetrating only the light transmitting substrate 110 by
about 170 degrees to about 190 degrees. The phase shifting layer
120 may have a light transmittance of from about 4% to about
50%.
[0018] The first light blocking layer 130 may be disposed on the
phase shifting layer 120. The first light blocking layer 130 may be
or include any suitable material. For example, the first light
blocking layer 130 may be or include a chrome (Cr) layer, an
aluminum (Al) layer, a tantalum (Ta) layer or a titanium nitride
(TiN) layer. The first light blocking layer 130 may have a light
transmittance of at most 5%.
[0019] The first resist layer 140 may be disposed on the first
light blocking layer 130. The first resist layer 140 and the second
light blocking layer 150 may act as etch buffer layers while the
first light blocking layer 130 is etched. Thus, at least the first
resist layer 140 should have a sufficient thickness T1 so that the
first resist layer 140 remains even after the first light blocking
layer 130 is etched. That is, an initial thickness (i.e., the
thickness T1) of the first resist layer 140 may be determined so
that the first resist layer 140 remains to have a certain thickness
even after the first resist layer 140 is exposed to an etch process
for patterning the first light blocking layer 130. The initial
thickness of the first resist layer 140 may be greater than the
certain thickness of the remaining first resist layer after the
first light blocking layer 130 is patterned. In an embodiment, the
thickness T1 of the first resist layer 140 may be at least 800
angstroms.
[0020] The second light blocking layer 150 may be disposed on the
first resist layer 140. As described above, the second light
blocking layer 150 and the first resist layer 140 may act as etch
buffer layers while the first light blocking layer 130 is etched.
The second light blocking layer 150 may be etched while the first
light blocking layer 130 is etched. Specifically, the second light
blocking layer 150 may include a material that can be completely
removed before an etch process for patterning the first light
blocking layer 130 is completed. Thus, the second light blocking
layer 150 may include a material having a higher etch rate than an
etch rate of the first light blocking layer 130. In an embodiment,
the second light blocking layer 150 may be provided by adding
oxygen atoms to the same material employed for the first light
blocking layer 130. The second light blocking layer 150 may have a
smaller thickness than a thickness of the first light blocking
layer 130.
[0021] The second resist layer 160 may be disposed on the second
light blocking layer 150. The second resist layer 160 directly
affects the pitch or the width of the fine patterns. Thus, the
second resist layer 160 may have a thickness T2 that is
sufficiently thin for forming fine patterns more accurately.
Accordingly, the thickness T2 of the second resist layer 160 may be
less than the thickness T1 of the first resist layer 140. For
example, the thickness T2 of the second resist layer 160 may be
from about 20% to about 50% of the thickness T1 of the first resist
layer 140. In an embodiment, in order for forming fine patterns
having a width of from about 15 nanometers to about 25 nanometers,
the thickness T2 of the second resist layer 160 may be of from
about 200 angstroms to about 400 angstroms.
[0022] FIGS. 2 to 7 are cross-sectional views illustrating a method
of fabricating a phase shift photomask using the phase shift
photomask blank 100 shown in FIG. 1.
[0023] Referring to FIG. 2, after the phase shift photomask blank
100 is provided, the second resist layer 160 of the phase shift
photomask blank 100 may be patterned for forming second resist
patterns 161 to 165. The second resist layer 160 may be patterned
using an electron beam (e-beam) lithography process. The second
resist patterns 162 to 165 may be formed in a pattern region 100A,
and the second resist pattern 161 may be formed in a frame region
100B. In the present embodiment, pattern images of the pattern
region 100A may be transferred onto a wafer while the frame region
100B does not include patterns whose images are transferred onto
the wafer. The frame region 100B may be disposed to surround the
pattern region 100A. The second resist pattern 161 may be formed to
cover an entire surface of the second light blocking layer 150 in
the frame region 100B. The second resist patterns 162 to 165 may be
formed to cover partially the second light blocking layer 150 in
the pattern region 100A. Accordingly, portions of the second light
blocking layer 150 in the pattern region 100A may be exposed by the
second resist patterns 162 to 165.
[0024] The second resist patterns 162 to 165 formed in the pattern
region 100A may have the same width. The second resist patterns 162
to 165 may have different widths. For example, the second resist
patterns 162 to 165 may have two different widths. For example, a
width of the second resist patterns 162 and 165 may be greater than
a width of the second resist patterns 163 and 164 as shown in FIG.
2. More specifically, in the embodiment of FIG. 2, the second
resist patterns 163 and 164 may correspond to fine patterns having
first and a second width W1, W2, respectively. The first width W1
may be equal to or different from the second width W2. Even though
the second resist patterns 163 and 164 are fine patterns having
relatively narrow widths, no collapse of the second resist patterns
163 and 164 may occur because the second resist patterns 163 and
164 are formed to be sufficiently thick to prevent such a
collapse.
[0025] Referring to FIG. 3, the second light blocking layer 150 may
be etched using the second resist patterns 161 to 165 as etch
masks, thereby forming second light blocking patterns 151 to 155
which are aligned with the second resist patterns 161 to 165.
Portions of the first resist layer 140 may be exposed by the second
light blocking patterns 151 to 155 and the second resist patterns
161 to 165. The second light blocking patterns 153 and 154 may have
substantially the same width as the second resist patterns 163, and
164. That is, the second light blocking patterns 153 and 154 may
have the first and second widths W1, W2, respectively.
[0026] Referring to FIG. 4, the first resist layer 140 may be
etched using the second resist patterns 161 to 165 and the second
light blocking patterns 151 to 155 as etch masks, thereby forming
first resist patterns 141 to 145 which are aligned with the second
resist patterns 161 to 165 and the second light blocking patterns
151 to 155. The etch process for forming the first resist patterns
141 to 145 may be performed using an anisotropic dry etch process.
The anisotropic dry etch process may employ an oxygen gas as an
etch gas. Since the second resist patterns 161 to 165 are thinner
than the first resist layer 140, the second resist patterns 161 to
165 may be removed while the first resist layer 140 is etched for
forming the first resist patterns 141 to 145. After the first
resist patterns 141 to 145 are formed, portions of the first light
blocking layer 130 may be exposed. The first resist patterns 143
and 144 may have substantially the same width as the second light
blocking patterns 153 and 154, respectively. That is, the first
resist patterns 143 and 144 may have the first and second widths W1
and W2, respectively.
[0027] Referring to FIG. 5, the first light blocking layer 130 may
be etched using the second light blocking patterns 151 to 155 and
the first resist patterns 141 to 145 as etch masks, thereby forming
first light blocking patterns 131 to 135 which are aligned with the
second light blocking patterns 151 to 155 and the first resist
patterns 141 to 145. Subsequently, the phase shifting layer 120 may
additionally be etched using the second light blocking patterns 151
to 155 and the first resist patterns 141 to 145 as etch masks,
thereby forming phase shifting patterns 121 to 125. Since a
thickness of the second light blocking patterns 151 to 155 is less
than a thickness of the first light blocking layer 130 and an etch
rate of the second light blocking patterns 151 to 155 is higher
than an etch rate of the first light blocking layer 130, the second
light blocking patterns 151 to 155 may be removed while the first
light blocking layer 130 is etched for forming the first light
blocking patterns 131 to 135. After the first light blocking
patterns 131 to 135 and the phase shifting patterns 121 to 125 are
formed, portions of the substrate 110 may be exposed. The first
light blocking patterns 133 and 134 may have substantially the same
width as the first resist patterns 143 and 144, respectively.
Similarly, the phase shifting patterns 123 and 124 may have
substantially the same width as the first resist patterns 143 and
144, respectively. That is, the first light blocking pattern 133
and the phase shifting pattern 123 may both have the first width
W1, whereas the first light blocking pattern 134 and the phase
shifting pattern 124 may both have the second width W2.
[0028] Referring to FIG. 6, the first resist patterns 141 to 145
may be removed to expose top surfaces of the first light blocking
patterns 132 to 135 in the pattern region 100A and a top surface of
the first light blocking pattern 131 in the frame region 100B. A
third resist pattern 170 may be formed to cover the first light
blocking pattern 131 in the frame region 100B. The third resist
pattern 170 may be formed to expose the first light blocking
patterns 132 to 135 and the substrate 110 in the pattern region
100A.
[0029] Referring to FIG. 7, the first light blocking patterns 132
to 135 in the pattern region 110A may be removed using an etch
process that employs the third resist pattern 170 as an etch mask.
As a result of removal of the first light blocking patterns 132 to
135, the phase shifting patterns 122 to 125 in the pattern region
110A may be exposed. After the first light blocking patterns 132 to
135 are removed, the third resist pattern 170 may be removed. As a
result, a phase shift photomask fabricated by the above processes
may include the phase shifting patterns 122 to 125 exposed in the
pattern region 110A and the phase shifting pattern 121 covered with
the first light blocking pattern 131 in the frame region 100B.
[0030] FIG. 8 is a cross-sectional view of a binary photomask blank
200, according to an embodiment of the invention.
[0031] Referring to FIG. 8, the binary photomask blank 200 may
include a first light blocking layer 230, a first resist layer 240,
a second light blocking layer 250 and a second resist layer 260
which are stacked sequentially on a substrate 210. The layers may
be stacked in the order shown in FIG. 8.
[0032] The substrate 210 may include a light transmitting material,
for example, a quartz material, a glass material, a silicon
material, a silicon nitride material or a silicon oxynitride
material.
[0033] The first light blocking layer 230 may be disposed on the
substrate 210. The first light blocking layer 230 may include a
chrome (Cr) layer, an aluminum (Al) layer, a tantalum (Ta) layer or
a titanium nitride (TiN) layer. The first light blocking layer 230
may have a light transmittance of at most 5%.
[0034] The first resist layer 240 may be disposed on the first
light blocking layer 230. The first resist layer 240 and the second
light blocking layer 250 may act as etch buffer layers while the
first light blocking layer 230 is etched. Thus, at least the first
resist layer 240 should have a sufficient thickness T3 so that the
first resist layer 240 remains even after the first light blocking
layer 230 is etched. That is, an initial thickness (i.e., the
thickness T3) of the first resist layer 240 may be determined so
that the first resist layer 240 remains to have a certain thickness
even after the first resist layer 240 is exposed to an etch process
for patterning the first light blocking layer 230. The initial
thickness of the first resist layer 240 may be greater than the
certain thickness of the remaining first resist layer after the
first light blocking layer 230 is patterned. In an embodiment, the
thickness T3 of the first resist layer 240 may be at least 800
angstroms.
[0035] The second light blocking layer 250 may be disposed on the
first resist layer 240. As described above, the second light
blocking layer 250 and the first resist layer 240 may act as etch
buffer layers while the first light blocking layer 230 is etched.
The second light blocking layer 250 may be etched while the first
light blocking layer 230 is etched. Specifically, the second light
blocking layer 250 may include a material that can be completely
removed before an etch process for patterning the first light
blocking layer 230 is completed. Thus, the second light blocking
layer 250 include a material having a higher etch rate than an etch
rate of the first light blocking layer 230. In an embodiment, the
second light blocking layer 250 may be provided by adding oxygen
atoms to the same material employed as the first light blocking
layer 230. The second light blocking layer 250 may a smaller
thickness than a thickness of the first light blocking layer
230.
[0036] The second resist layer 260 may be disposed on the second
light blocking layer 250. The second resist layer 260 may directly
affect the pitch or width of the fine patterns. Thus, the second
resist layer 260 may have a thickness T4 that is sufficiently thin
for accurately forming fine patterns. Accordingly, the thickness T4
of the second resist layer 260 may be less than the thickness T3 of
the first resist layer 240. For example, the thickness T4 of the
second resist layer 260 may be from about 20% to about 50% of the
thickness T3 of the first resist layer 240. In an embodiment, for
forming fine patterns having a width of from about 15 nanometers to
about 25 nanometers, the thickness T4 of the second resist layer
260 may be of from about 200 angstroms to about 400 angstroms.
[0037] FIGS. 9 to 13 are cross-sectional views illustrating a
method of fabricating a binary photomask using the binary photomask
blank 200 shown in FIG. 8.
[0038] Referring to FIG. 9, after the binary photomask blank 200 is
provided, the second resist layer 260 of the binary photomask blank
200 may be patterned for forming second resist patterns 261 to 265.
For example, the second resist layer 260 may be patterned using an
electron beam (e-beam) lithography process. The second resist
patterns 262 to 265 may be formed in a pattern region 200A, whereas
the second resist pattern 261 may be formed in a frame region 200B.
In the present embodiment, pattern images of the pattern region
200A may be transferred onto a wafer. By contrast, the frame region
200B does not include patterns whose images are transferred onto
the wafer. The frame region 200B may be disposed to surround the
pattern region 200A. The second resist pattern 261 may be formed to
cover an entire surface of the second light blocking layer 250 in
the frame region 200B. The second resist patterns 262 to 265 may be
formed to cover partially the second light blocking layer 250 in
the pattern region 200A. Accordingly, portions of the second light
blocking layer 250 in the pattern region 200A may be exposed by the
second resist patterns 262 to 265.
[0039] The second resist patterns 262 to 265 formed in the pattern
region 200A may have the same width. The second resist patterns 262
to 265 may have different widths. The second resist patterns 262 to
265 may have two different widths. For example, a width of the
second resist patterns 262 and 265 may be greater than a width of
the second resist patterns 263 and 264. In the present embodiment,
the second resist patterns 263 and 264 may correspond to fine
patterns having first and second widths W3 and W4, respectively.
The first width W3 may be equal to or different from the second
width W4. Even though the second resist patterns 263 and 264 are
fine patterns having relatively narrow widths, no collapse of the
second resist patterns 263 and 264 may occur because the second
resist patterns 263 and 264 are formed to be sufficiently thick to
prevent such collapse.
[0040] Referring to FIG. 10, the second light blocking layer 250
may be etched using the second resist patterns 261 to 265 as etch
masks, thereby forming second light blocking patterns 251 to 255
which are aligned with the second resist patterns 261 to 265.
Portions of the first resist layer 240 may be exposed by the second
light blocking patterns 251 to 255 and the second resist patterns
261 to 265. The second light blocking patterns 253 and 254 may have
substantially the same width as the second resist patterns 263 and
264. That is, the second light blocking patterns 253 and 254 may
have the first and second widths W3 and W4, respectively.
[0041] Referring to FIG. 11, the first resist layer 240 may be
etched using the second resist patterns 261 to 265 and the second
light blocking patterns 251 to 255 as etch masks, thereby forming
first resist patterns 241 to 245. The first resist patterns 241 to
245 may be aligned with the second resist patterns 261 to 265 and
the second light blocking patterns 251 to 255. The etch process for
forming the first resist patterns 241 to 245 may be performed using
an anisotropic dry etch process. The anisotropic dry etch process
may employ an oxygen gas as an etch gas. Since the second resist
patterns 261 to 265 are thinner than the first resist layer 240,
the second resist patterns 261 to 265 may be removed while the
first resist layer 240 is etched for forming the first resist
patterns 241 to 245. After the first resist patterns 241 to 245 are
formed, portions of the first light blocking layer 230 may be
exposed. The first resist patterns 243 and 244 may have
substantially the same width as the second light blocking patterns
253 and 254, respectively. That is, the first resist patterns 243
and 244 may have the first and second widths W3 and W4,
respectively.
[0042] Referring to FIG. 12, the first light blocking layer 230 may
be etched using the second light blocking patterns 251 to 255 and
the first resist patterns 241 to 245 as etch masks, thereby forming
first light blocking patterns 231 to 235. The first light blocking
patterns 231 to 235 may be aligned with the second light blocking
patterns 251 to 255 and the first resist patterns 241 to 245. Since
a thickness of the second light blocking patterns 251 to 255 is
less than a thickness of the first light blocking layer 230 and an
etch rate of the second light blocking patterns 251 to 255 is
higher than an etch rate of the first light blocking layer 230, the
second light blocking patterns 251 to 255 may be removed while the
first light blocking layer 230 is etched for forming the first
light blocking patterns 231 to 235. After the first light blocking
patterns 231 to 235 are formed, portions of the substrate 210 may
be exposed. The first light blocking patterns 233 and 244 may have
substantially the same width as the first resist patterns 243 and
244, respectively. That is, the first light blocking patterns 233
and 234 may have the first and second widths W3 and W4,
respectively.
[0043] Referring to FIG. 13, the first resist patterns 241 to 245
may be removed to expose top surfaces of the first light blocking
patterns 231 to 235. As a result, a binary photomask fabricated by
the above processes may include the first light blocking patterns
232 to 235 disposed to expose portions of the substrate 210 in the
pattern region 210A and the first light blocking pattern 231
disposed to cover an entire surface of the substrate 210 in the
frame region 200B.
[0044] The embodiments of the present disclosure have been
disclosed above for illustrative purposes. Those of ordinary skill
in the art will appreciate that various modifications, additions,
and substitutions are possible, without departing from the scope
and spirit of the present disclosure as disclosed in the
accompanying claims.
* * * * *